1. Field of the Invention
The present invention relates generally to a heat exchanger having a metallic tank, for cooling automobile engine coolant or for use in an oil cooler, a condenser, etc., and more particularly to a tank-pipe connection structure of such a heat exchanger, where a pipe for fluid entry is projectingly secured to the metallic tank of the heat exchanger.
2. Description of the Related Arts
In cases where the heat exchanger tank is formed from a metal plate of aluminum, etc., the tank includes a pipe connection opening, to which an elongated metal pipe is brazed at its one end. To effect the brazing, parts of the heat exchanger are put together, the resultant assembly is placed in a furnace at a higher temperature. Brazing materials previously coated on the outer surface of the pipe and other parts are fused and then cooled and solidified so that brazing is securely and integrally made between the pipe and the tank and between the parts.
When the assembled heat exchanger is introduced, with a relatively elongated pipe projecting from the tank sidewall, into the high temperature furnace, the furnace tends to have therein a poor holding capacity for the heat exchangers. More specifically, when each heat exchanger has an elongated pipe for fluid entry fairly projecting therefrom, the other heat exchangers need to be held apart from each other within the furnace, making it difficult to house a multiplicity of heat exchangers at one time. This may impair the mass-productivity of the heat exchangers and thus raise the production costs of the heat exchangers.
It may also be troublesome per se to firmly secure the relatively elongated pipe for fluid entry to the tank sidewall previous to brazing.